RHCSA Systemd and Service Management Flashcards

Which directive in a unit file's `[Service]` section sets environment variables for the process?

Answer: Environment=

`Environment=` sets key=value environment variables directly in the unit file's `[Service]` section.

How do you make journald persist logs across reboots on a RHEL system where it is not yet doing so?

Answer: Create /var/log/journal/ directory and restart systemd-journald

Creating `/var/log/journal/` causes journald to automatically switch to persistent storage on restart.

A unit file has `ConditionPathExists=/etc/myapp.conf`. What happens if that file does not exist when the unit is started?

Answer: The unit is skipped silently as if it succeeded

When a `Condition*=` check fails, systemd skips the unit without error — it reports as 'success' but does nothing.

Which systemctl subcommand shows all currently loaded and active socket units?

Answer: systemctl list-units --type=socket

`systemctl list-units --type=socket` filters the active unit list to show only socket units.

What is the correct way to view the full content of a unit file including overrides using systemctl?

Answer: systemctl cat httpd.service

`systemctl cat` prints the full unit file content including all applicable drop-in override files.

A service has `After=postgresql.service` but NOT `Requires=postgresql.service`. What is the practical effect?

Answer: The service starts after PostgreSQL if PostgreSQL is being started, but starts regardless otherwise

`After=` only controls ordering; without `Requires=` or `Wants=`, there is no dependency — only sequencing if both happen to activate.

Which command sets `graphical.target` as the default boot target?

Answer: systemctl set-default graphical.target

`systemctl set-default graphical.target` updates the `default.target` symlink to point to `graphical.target`.